FXUS64 KSJT 050942
AFDSJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN ANGELO TX
342 AM CST SUN FEB 5 2012

.SHORT TERM...
A SHORTWAVE TROUGH EMBEDDED IN SOUTHWEST FLOW ALOFT WILL MOVE
ACROSS SOUTH TEXAS TO THE UPPER TEXAS COAST TODAY. EXPECT THE RAIN
WITH THIS SYSTEM TO STAY SOUTH OF OUR AREA. KEEPING POPS BELOW 15
PERCENT IN OUR SOUTHERNMOST COUNTIES...WHERE ONLY A FEW SPRINKLES
FROM A MID-LEVEL CLOUD DECK ARE POSSIBLE AT BEST. MID TO UPPER
LEVEL CLOUD SHIELD WILL REMAIN OVER MOST OF OUR AREA...BUT THE
NORTHERN BIG COUNTRY WILL BE ON THE EDGE OF THIS AND SHOULD SEE
PARTLY CLOUDY SKIES OVERALL. WITH THE CLOUD COVER AND SOME
CONTINUED COLD AIR ADVECTION TODAY WITH NORTH-NORTHEAST LOW-LEVEL
FLOW... A LIMITED TEMPERATURE RECOVERY INTO THE UPPER 40S TO LOWER
50S IS EXPECTED FOR HIGHS TODAY. THE COLDER READINGS SHOULD BE
ACROSS THE WESTERN BIG COUNTRY. WIND SPEEDS WILL BE A LITTLE LOWER
TODAY...MOSTLY IN THE 10-15 MPH RANGE.

WINDS WILL BECOME LIGHT TONIGHT AS SURFACE HIGH PRESSURE SETTLES
INTO OKLAHOMA AND NORTHWESTERN TEXAS. LOW TEMPERATURE FORECAST
TONIGHT IS A BIT TRICKY...AND WILL DEPEND ON EXTENT OF CLOUD COVER
DECREASE. ANTICIPATE THE BIG COUNTRY HAVING THE LEAST AMOUNT OF
CLOUD COVER... WITH SKIES BECOMING PARTLY CLOUDY OVERNIGHT FARTHER
SOUTH. THE COLDEST MINIMUM TEMPERATURES EXPECTED ACROSS THE BIG
COUNTRY /MOSTLY IN MID TO UPPER 20S/ WITH 30S ACROSS OUR CENTRAL AND
SOUTHERN COUNTIES. THESE READINGS ARE ABOVE GUIDANCE...WHICH HAS A
TENDENCY IN RECENT WEEKS TO BE A LITTLE TOO COLD WITH THE LOW
TEMPERATURES. HOWEVER...IF LATER FORECAST CLOUD COVERAGE DECREASE
IS MORE THAN CURRENTLY ANTICIPATED...A DOWNWARD ADJUSTMENT TO
OVERNIGHT LOWS WILL BE NEEDED.

19

&&

.LONG TERM...
THE LONG TERM WILL HAVE A RATHER AUSPICIOUS BEGINNING WITH PLEASANT
WEATHER ANTICIPATED MONDAY AND TUESDAY FOLLOWED BY COOLER AND
POSSIBLY WET CONDITIONS DURING THE LATTER HALF OF THE WEEK. THE
DOUBLE BARREL TROF LOCATED OVER THE WESTERN 2/3 OF THE CONUS WILL
BE A PLAYER OVER THE NEXT SEVERAL DAYS. THE EASTERN LOW CURRENTLY
LOCATED NEAR KANSAS CITY WILL SCOOT OFF TO THE EAST TODAY WHILE THE
LARGER CYCLONE OVER THE GREAT BASIN WILL SLOWLY DEEPEN AND CRAWL
EAST ACROSS THE ROCKIES. BY LATE MONDAY... THE LOW IS PROGGED TO
BE CENTERED OVER CO WITH A BROAD SOUTHWEST FLOW ALOFT ACROSS THE
SOUTHERN PLAINS. MOST OF THE LOW LEVEL MOISTURE WILL BE TO THE
SOUTH AND EAST OF THE CWA SO NO PRECIP IS ANTICIPATED DESPITE
DECENT MID LEVEL OMEGA FIELDS MONDAY NIGHT AS THE TROF PASSES. THE
ATTENDANT SURFACE COLD FRONT WILL MOVE INTO THE TX PANHANDLE
MONDAY NIGHT AND SHOULD MOVE THROUGH WEST CENTRAL TX ON TUESDAY.
TEMPS ARE STILL EXPECTED TO WARM INTO THE UPPER 50S AND LOWER 60S
ACROSS MUCH OF THE AREA BUT PORTIONS OF THE BIG COUNTRY MAY NOT
CLIMB OUT OF THE LOWER 50S.

ON TUESDAY...THE MEDIUM RANGE MODELS INDICATE THAT A POTENT
MID/UPPER LEVEL TROF WILL CUT OFF FROM THE MAIN FLOW JUST OFF THE
WEST COAST. THIS FEATURE IS DEPICTED AS SLIDING DOWN THE WEST COAST
ACROSS CA AND ALONG THE BAJA PENINSULA THROUGH THURSDAY BEFORE
MAKING A TURN TO THE EAST A THE WEEK/S END. THE GFS IS SLIGHTLY
FASTER WITH THE EJECTION OF THIS FEATURE WHEREAS THE ECMWF HANGS THE
LOW JUST OFF THE WEST COAST OF MEXICO THROUGH 12Z SATURDAY. IT ALSO
APPEARS THAT THE OPERATIONAL GFS IS AMONG THE FASTER OF THE ENSEMBLE
MEMBERS. WITH THAT SAID...STRONG UPPER LEVEL DIVERGENCE DOWNSTREAM
OF THE UPPER TROF WILL PROMOTE WIDESPREAD MID AND HIGH CLOUDS ON
WEDNESDAY...KEEPING TEMPS IN THE 50S. WE COULD SEE SOME LIGHT
SHOWERS BY WEDNESDAY NIGHT AS A LEAD SHORTWAVE TROF MOVES ACROSS
THE BIG BEND. HOWEVER...EXPERIENCE SUGGESTS THAT THIS FIRST WAVE
MAY BE DELAYED A BIT...HOLDING OFF UNTIL THURSDAY. ON THURSDAY...
THE LOW LEVELS WILL MOISTEN AND WE WILL SEE ENHANCED MESOSCALE
FORCING AS THE H25 JET ROUNDS THE BASE OF THE TROF. THIS SHOULD
PRESENT A DECENT OPPORTUNITY FOR RAIN SHOWERS ACROSS MOST OF THE
AREA ALTHOUGH WITH THE LACK OF QPF GENERATED BY THE ECMWF...I
CHOSE NOT TO GO HIGHER THAN 30 PERCENT FOR NOW.

THIS PATTERN WILL HOLD ON FRIDAY WITH COOL AND WET CONDITIONS
EXPECTED ONCE AGAIN. TEMPS WILL LIKELY BE A BIT COLDER AS WE SEE A
SURGE OF COLDER AIR MOVE INTO THE AREA FROM THE NORTH. POPS REMAIN
GRADED FROM SLIGHT CHANCE IN THE NORTH TO CHANCE IN THE SOUTH.
DRIER AIR ON FRIDAY NIGHT SHOULD ALLOW PRECIP CHANCES TO COME TO
AN END WITH IMPROVING WEATHER ANTICIPATED OVER THE WEEKEND.
OVERNIGHT TEMPS FRIDAY NIGHT MAY FALL INTO THE UPPER 20S BASED ON
THE CURRENT TIMING OF THE SYSTEM BUT THAT COULD EASILY CHANGE IF
THE SYSTEM SLOWS DOWN BY ANOTHER DAY. I HAVE SHOWN A WARMING TREND
AT THE END OF THE FORECAST PERIOD WITH TEMPS BACK IN THE MID 60S
BY SUNDAY.

JOHNSON

&&

.PRELIMINARY POINT TEMPS/POPS...
ABILENE 50 30 53 34 56 / 0 10 0 0 10
SAN ANGELO 52 34 56 33 60 / 10 0 0 0 0
JUNCTION 53 38 56 30 62 / 10 10 0 0 0

&&

.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

25/19



Back to Main Forecast Discussion Page